Percentage Change (CHANGE) compares the source with its own value a fixed number of bars back. It divides the current value by the value length bars ago and subtracts one, so the result is a fraction: 0.01 is a one percent rise, -0.02 a two percent fall, and 1 a doubling.
The first length bars have no earlier value to compare with and are left blank. A bar whose earlier value is zero is also left blank rather than dividing by zero. With the default length of one, the line is the bar-to-bar return of the source.
How to read Percentage Change (CHANGE)
Read the line around zero. Above zero the source is higher than it was length bars ago, below zero it is lower, and the distance from zero is the size of the move as a fraction. Spikes show the largest moves over the chosen span, and a line that stays near zero shows a market that has gone nowhere over that span.
The value is a ratio, so it compares fairly across price levels: a one percent move reads the same whether price is high or low. It measures only the start and end of the span and says nothing about the path in between.
Settings
- Source
- The price series to measure, such as the close or the bar midpoint.
- Length
- How many bars back the comparison reaches. One gives the bar-to-bar change; a larger value gives the change over a longer span.
Frequently asked questions
Why is the value 0.01 and not 1 for a one percent rise?
The line is the raw ratio minus one, a fraction rather than a number of percent. Multiply by 100 to read it in percent.
Why are the first bars blank?
Each value needs the source from length bars earlier. Until that many bars exist there is nothing to compare with, so the study draws nothing.
How is it different from momentum?
Momentum is usually the difference between the two prices, in price units. This is their ratio minus one, so it is independent of the price level.
